Fluoroelastomers are a class of synthetic rubbers which provide high levels of resistance to chemicals, fuels, oils and heat. The heat stability and oil resistance of these materials are generally considered to be due to the high ratio of fluorine to hydrogen, the strength of the carbon-fluorine bond, and the absence of unsaturation. Fluoroelastomers are used, for example, as lining in fuel lines, and, as such, their fuel barrier properties are an important factor.
Minerals and other inorganic materials are often used as fillers in fluoroelastomers, principally to reduce the cost of these high value compounds. For example, EP 1591479 A1 describes a fluoroelastomer composition comprising carbon black as filler. US 2003/0125463 A1 and U.S. Pat. No. 7,138,470 describe fluoroelastomer compositions comprising inorganic fillers such as barium sulfate, wollastonite, silica, carbon black and titanium dioxide.
Whilst inexpensive filler materials are available, it would be desirable to provide further fluoroelastomer compositions comprising alternative, preferably inexpensive, filler materials having desirable properties across a variety of end uses, whilst preserving, or even improving upon, the general physical, mechanical and chemical properties of the fluoroelastomer compositions.